1. Technical Field
The present disclosure relates to a device capable of detecting a particular substance.
2. Background Art
There is an apparatus such as an air conditioner which includes a gas detecting device. The gas detecting device can detect a presence or an absence of a particular gas, a concentration of a gas, and others by utilizing characteristics of a variety of gases which absorb infrared light in different wavelengths for each gas. The air conditioner including the gas detecting device is capable of switching between an external air circulation mode and an internal air circulation mode based on a concentration of a gas such as carbon dioxide output from the gas detecting device.
FIGS. 44 and 45 are a cross-sectional view and an exploded perspective view, respectively, illustrating a conventional gas component detecting device described in Unexamined Japanese Patent Publication No. 2012-220353 (hereinafter referred as PTL). The gas component detecting device of the PTL includes circuit block 1001 and optical block 1002.
In circuit block 1001, body 1010 accommodates light emitting unit 1003, light receiving unit 1004, wavelength filter 1005, and wiring board 1011 within recess 1100. Light emitting unit 1003 emits infrared light easily absorbable by a detection target gas. Light receiving unit 1004 receives infrared light and converts the received light into an electric signal. Wavelength filter 1005 constitutes a band pass filter which has a wavelength band as a transmission band containing a wavelength of infrared light emitted from light emitting unit 1003. Signal processing circuit unit 1006 is mounted on wiring board 1011. Signal processing circuit unit 1006 drives light emitting unit 1003 to allow emission of infrared light from light emitting unit 1003. In addition, signal processing circuit unit 1006 processes the signal output from light receiving unit 1004. Body 1010 is provided with a plurality of insert-molded terminals 1012 (see FIG. 45). Terminals 1012 are electrically connected with wiring board 1011.
In optical block 1002, cover 1020 accommodates light guide 1008 therein. Light guide 1008 is composed of first reflection mirror 1080, second reflection mirror 1081, third reflection mirror 1082, and fourth reflection mirror 1083. According to the gas detecting device, fourth reflection mirror 1083 closes an opening of recess 1100 of body 1010. Cover 1020 in a state accommodating light guide 1008 within recess 1200 is joined with body 1010. Cover 1020 is provided with air hole 1201 formed at a center thereof and penetrating cover 1020. According to the gas detecting device, dust filter 1007 covers air hole 1201.
According to the gas detecting device of the PTL, outside air containing the detection target gas is introduced into light guide 1008 via air hole 1201. According to the gas detecting device, an amount of infrared light received by light receiving unit 1004 decreases by absorption of the infrared light, emitted from light emitting unit 1003, by the detection target gas. The gas detecting device detects a concentration of a gas component based on a processing result of the signal output from light receiving unit 1004 by processing circuit unit 1006. The gas detecting device is capable of outputting a detection signal indicating the concentration of the gas component to the outside via terminals 1012.
FIG. 46 is a perspective view illustrating conventional gas detector 1310 described in WO 2005/012869. Gas detector 1310 includes emitter 1332 capable of emitting emission energy, sensors 1334A and 1334B, and housing 1318.
Housing 1318 includes side walls 1318A, 1318B, 1318C, and 1318D, and opening 1318E. In gas detector 1310, a detection gas flows in a direction of an arrow G with respect to opening 1318E of housing 1318. Sensor 1334A includes optical filter 1336A. Optical filter 1336A transmits light having a wavelength to be absorbed by the detection gas. Sensor 1334B includes optical filter 1336B. Optical filter 1336B does not transmit the light having the wavelength to be absorbed by the detection gas. Housing 1318 includes concave mirrors 1338A and 1338B. According to gas detector 1310, the emission energy emitted from emitter 1332 reflects on a surface of concave mirror 1338A, and enters sensor 1334A via filter 1336A (see fine solid line arrows in FIG. 46). Similarly, according to gas detector 1310, the emission energy emitted from emitter 1332 reflects on a surface of concave mirror 1338B, and enters sensor 1334B via filter 1336B. Each of sensors 1334A and 1334B outputs a signal corresponding to the entering emission energy. These signals are input to control circuit 1316. Control circuit 1316 displays a concentration of the detection gas on display 1320 based on the input signals.